The moral debate over same-sex marriage in Illinois will likely intensify in the coming months, as a pair of lawsuits challenging the state’s gay marriage ban begin to work through the Cook County courts. But there’s already a parallel constitutional turf war over a question that has faced gay rights advocates, law professors and political scientists across the country for years: To sue or not to sue?

The argument over who should rule on gay marriage - judges in state courts or lawmakers in state capitals - began to heat up last week even before lawyers for the 25 same-sex couples suing to overturn Illinois’ gay marriage prohibition had their first court date.

“Let’s be clear: The legislature remains free to act on marriage. We invite them to do so,” John Knight, the American Civil Liberties Union of Illinois’ head lawyer in its case, said at a downtown news conference announcing the lawsuilts last week. “But lesbian and gay couples in Illinois have waited long enough for marriage and they’re hurt every day that the delay continues.”

Before the crowd of reporters and plaintiffs even had a chance to clear out of the conference room, gay marriage opponents were waiting outside the door, ready to stake their position on the courthouse-versus-state house debate.

“You don’t do end-runs around the people by going to courts and having things struck down in this way,” said Peter Breen, head of the Chicago-based Thomas More Society, a conservative non-profit law firm.  “I don’t see they’re gonna be successful here.”

This fight isn’t just a legalistic one. Gay rights advocates in Illinois say they’ve been waiting for years to find the right moment to challenge the state’s laws, and a tactical miscalculation could result in an unfavorable court verdict or political backlash, as it has in other states.

The danger lies in state judges issuing a legal opinion that doesn’t jive with public opinion, said University of Chicago political science and law professor Gerald Rosenberg, who has studied the political effects of some same-sex marrige court decisions.

“To many people in a democracy, a judicial decision seems undemocratic,” Rosenberg said. “When you’re dealing with a notion like equality, which is very ambiguous, who in society ought to be able to decide what it means?”

The danger for same-sex marriage advocates is in the numbers, Rosenberg said. 38 states now prohibit gay marriage, and the vast majority of those laws and constitutional amendments were approved in the last twenty years, when state court decisions began to bring the debate into the foreground.

But moving through the courts is a smart tactical move in Illinois, where gay marriage legislation is stalled in the General Assembly, said Thomas Keck, a political science and law professor at Syracuse University.

“And so from the advocates’ perspective, it’s got - I mean, you gotta try to push forward everywhere, right? And see where there’s some play,” Keck said.

Eight states and the District of Columbia have approved gay marriage; state courts had a hand in four of those decisions, while the other five jurisdictions moved through their elected bodies. New Jersey’s state legislature approved gay marriage in Februrary, though Republican Gov. Chris Christie has vetoed the bill.

The legal climate in Illinois seems to be growing friendlier for advocates of gay marriage. Late Friday afternoon, Democratic Illinois Attorney General Lisa Madigan’s office handed a small victory to gay rights advocates when her office quietly filed papers in Cook County Court indicating it would not defend the state’s same-sex marriage ban. Democratic Gov. Pat Quinn for the first time last month said publicly that he supports same-sex marriage, following a similar declaration by President Barack Obama during an interview with ABC News just a few days prior.

A spokesman for Cook County State’s Attorney Anita Alvarez declined to say whether her office would defend the state’s gay marriage ban in county court.